Drill-bit.



A. W. TAYLOR.

DRILL BIT.

APPLICATION FILED JULY 24, 1913.

1,088,481 Patented Feb. 24, 1914. i?? 1 i?? 6 Wzmy` 5` A By M rfy yATTORNEYS ALBERT WALKENS TAYLOR, OF PECKVILLE, PENNSYLVANIA.

DRILL-BIT.

Specification of Letters Patent.

Patented Feb. 24, 1914.

Application filed July 24. 1913. Serial No. 780,940.

I0 all whom imag concern:

Be it known that I, ALBERT W. TAYLOR, a citizen of the United States,and a resident of Peckville, in the county of Lackawanna and State ofPennsylvania, have invented a new and Improved Drill-Bit, of which thefollowing is a full, clear, and exact description.

My invent-ion, while useful in rock drilling, is more particularlydesigned for drilling coal in coal mining. Ordinary drills used in coalmining have a tendency to run olf or be deflected when striking sulfurand various hard substances liable to be encountered, the result beingthat the hole produced is not straight for the ready insertion of thecartridge. The ordinary drill also does not turn easily.

It is a design of my invention to provide a drill that will readily cutthrough hard substances, and a drill that may be turned easily in thedrill hole and that will produce a straight smooth hole to properlyreceive the cartridge.

TheJ invention also has for it-s design to provide a plural bit, theelements of which may be readily removed and renewed.

The invention will be more particularly explained in the specificdescription following.

Reference is to be had to the accompanying dra-wings forming a part ofthis specification, in which similar characters of reference indicatecorresponding parts in all the views.

Figure 1 is a side elevation of a drill bit embodying my invention; Fig.2 is a front view thereof; Fig. 3 is an inverted cross section takenthrough the clamp band for the outer bit elements; Fig. 4 is an invertedcross section taken below the clamp band; Fig. 5 is a vertical section;Fig. 6 is a top plan view; and Fig. 7 is a perspective view of one ofthe outer bit elements.

In forming a. bit in accordance with my invention, a head or body 10 isprovided, having a shank 11 adapted for ordinary drill sockets, and saidhead has an axial bore 12 to receive the stem 13 of the central bitelement 14:. A set screw 15 passes transversely into the head 10, itsinner end being adapted to enter an annular groove 16 in the stem 13,and to bind against the stem 13 at said groove. At the base of the stem13 the element 111 has a polygonal or equivalent angular enlargement 17,which is received 1n a recess or depression 18 formed inthe under sideo-r face of the head 10 complementary to the axial bore l2, to assist inpreventing the turning. of the bit 14 in the head. 'Ihe cutting membersof the bit 14 lnclude a centraltooth 19, and broader lateral cutters 20,which are preferably so forged and ground that the front total cuttingedge of the bit 111 is of general spiral form, as seen in the frontview, Fig. 2.

Diagonal openings 21 lead upwardly and outwardly from the axial bore 12at the top through which a nail or other tool may be entered to driveout the stem 13, should the bit break and the stem bind.

In connection with the central bit I employ a series of lateral bitelements 22, preferably vfourfin number. The bits 22 seat againstlateral faces or seats 23 formed on the sides of the head, 10, the saidseats inclining downwardly and outwardly to correspondingly dispose thebit elements 22. The side walls 24 of the seats 23 form with said seatsdove-tail grooves for the bit elements 22, and the latter arecorrespondingly dovetailed 'in cross section, as clearly shown in Fig.4. At the inner side of each bit element 22 an upwardly facing shoulder25 is produced, adapted to come to a bearing against the under side orface of the head 10 outsidel of the central bit element 14. The upperends of the bit elements 22 are adapted to lie beneath the' lateralprotuberances 26 that overhang the seats 23 at the upper ends,presenting shoulders 27 against which the upper ends of the bit elementsmay abut. A split clamp band 28 encircles the head 10 and embraces' theseveral bit elements 22, being received in transverse grooves 29 in theupper ends ,of the said bit elements. The ends of the clamp band 28overlap and have holesadapted to aline and receive the binding screw 15,whereby the said binding screw serves to fasten the clamp band of thelateral bit elements, and also the centra-l bit element 14.

The cutting point of each of the drill elements 22 is broadened towardthe lower edge and extends laterally to present the greatest total widthat the cutting edge, the outer sides 30 being preferably formed onrounding lines, as best seen in Figs. 1 and 5. The cutting edge 31 ofeach bit element is concavO-convex, the result being that the lateralbits effectively cut the material left by the central bit'elements andproduce a hole in which the drill has perfect clearance.

To provide clearance passages for the cuttings produced by the drills,depressions or longitudinal grooves '32 vextend along the sides of thehead 10 between the lateral bit elements 22, and between theprotuberances 26.

I have found in practice that a drill formed in accordance with myinvention has a greatly increased speed of performance in drilling holesin coal. The construction also makes possible the ready and convenientrepair or renewal of the bit elements.

Having thus described my invention', I claim as new and desire to secureby Letters Patent: y

1. A drill bit, comprising a head having an axial bore, a central bitelement havin a stem tting said bore, a series of lateral it elements onthe head outside'the central bit element, a clamp band embracing theouter an axial bore, a central bit element having a stem fitting saidbore, a series of lateral bit elements on the head outside the centralbit element, a clamp band embracing the outer bits, and a transverse setscrew in said head forming a fastener for said band and adapt- 'ed alsoto engage the stem of the central bit,

eral spiral form, a series of bit elements seated on lateral faces ofthehead outside of the central bit, and means for fastening the` v severalbits.

In testimony whereof I have signed my name to this specification in` thepresence of twosubs'cribing witnesses.

"ALBERT WALKENS TAYLOR.

Witnesses:

FREDERICK R. KRUrP, GEO. G. JAY.

